I love games that can be played in a co-op environment as well! So it's got that going for it! The art is cute and sound effects are bubble, which fits in with the rest of the game well.
I would say, if you were to continue evolving the game:
- It needs more variety than two types of enemies (which are actually just one kind)
- Some reason to keep the player coming back, the score is nice, presenting the player with some sort of graphic that represents "this much more to beat your high score" or "you've surpassed the high score by this much"
- More things to do. Killing enemies is nice, but am I supposed to pick up coins? or powerups? What can I carry forward from playing the game once, why should I come back? Do I collect coins to unlock skins? other characters? different powerups?
The core mechanic is solid, and its a cute little co-op party game, but now comes the building blocks on top of that.
Overall, very nice little jam game!